I am thinking of ordering some output transformers from Ali Express. I haven’t used them before but thought I would give it a go.
I am going to build an EL84 or 6P14P-EV PP amp.
Can you give some feed back on the following transformers with pros and cons and if it were you what would you order?
No.1
The first ones are
￡34.13 | 12W 8K/10k small push-pull output transformer, 6P1，EL84，6v6 tube amplifier output transformer, Primary overcurrent ≥80ma
12W 8K/10k small push pull output transformer, 6P1，EL84，6v6 tube amplifier output transformer, Primary overcurrent ≥80ma|Transformers| - AliExpress
Description
High quality 12W 8K/10k small push-pull output transformer
Steel sheet size: 66*30m (tongue width 22*30)
Manufacturer: Kawasaki, Japan
Primary resistance: PP 10K (resistance can be adjusted as required or super linear taps can be added)
Level impedance: 0-4-8Ω
Primary DC resistance: P-P248Ω, the error of the two arms is less than 0.5%
Grade DC resistance: 0-4: 0.35Ω, 0-8: 0.45Ω
Primary inductance: 28H
Primary overcurrent: not less than 80ma
Frequency response: 8-50KH z-1db, 20-35KHZ -0.3db
Withstand voltage: 2000Vdc
Weight: 1.85KG (net weight, without potting)
No.2
Going up in price are these ones
￡42.96 | 12W 8K: 4Ω 8Ω ultra-linear push-pull output transformer, 40H, suitable for 6P6P, 6V6, EL84, 6P14, 6BQ5 push-pull amplifier
12W 8K: 4Ω 8Ω ultra linear push pull output transformer, 40H, suitable for 6P6P, 6V6, EL84, 6P14, 6BQ5 push pull amplifier|Transformers| - AliExpress
Description
Luge PW-1 broadband response ultra-linear push-pull 8K/4Ω 8Ω output transformer, imitating the output transformer of Shanghai Meiduo brand electron tube R10-2 amplifier.
Mido R10-2 high-fidelity amplifier domestic classic HIFI amplifier, launched by Shanghai Radio No. 3 Factory in 1971, was also the most representative high-fidelity tube amplifier at the time. The characteristic of Mido R10-2 high-fidelity amplifier is that it does not hesitate to build Hi-Fi on the output transformer. The output transformer and the power transformer are the same size, which is very rare in the past tube audio. Not only is the material heavy, but the workmanship is very good, the sound is extraordinary.
Mido R10-2 high-fidelity output transformer adopts four-clamp one-winding method, adopts a core with a large cross-sectional area, increases the number of turns of the primary coil, and has a unique winding structure. The effect is outstanding, and the sound quality is now not used to lose thousands Imported transformers of the same specifications.
Z11 core winding measurement system, 76 pieces stacked 40mm thick, wide frequency response, large dynamic, delicate sound! The effect is immediate!
12W8K push-pull amplifier output cattle, suitable for 6P6P, 6V6, EL84, 6P14, 6BQ5 and other tube push-pull amplifier
Iron core is inserted into the core, nylon wire wrapped skeleton, high-quality oxygen-free copper enameled wire winding, using 4 clips 3, positive and negative winding, layered section winding, to minimize leakage inductance and distributed capacitance.
When the parameters are measured at 1KHZ, the inductance of P1 P2 is about 40H, the leakage inductance is about 60mH, and the distributed capacitance is 2300PF.
The primary copper resistance of P1, P2 is about 475Ω, the secondary 4 ohm copper resistance is about 0.5Ω, and the 8Ω copper resistance is about 0.6Ω.
The total volume is 80×69×70mm, and the weight is 2.8Kg/pair.
No.3
The next one is an amorphous C core design
View attachment 1
￡75.20 | 12W Amorphous C-type Core Push-pull Output Transformer Pr10K Se 0-4-8 Ohms for Tube Amplifier 6P1 6P14 EL84
12W Amorphous C type Core Push pull Output Transformer Pr10K Se 0 4 8 Ohms for Tube Amplifier 6P1 6P14 EL84|Transformers| - AliExpress
Amorphous C-type iron core 12W10K push-pull output transformer cattle 6P1.6P14, EL84 push-pull machine for application, layer winding process, CNC drying! Vacuum dipping paint!
Friends of the fever industry have a lot of controversy about the various output transformers that are processed by EI iron core and amorphous iron core. The C core has a good magnetic circuit distribution structure. Similar to the cores of 3,068a and 171 of the Western iron core, this type of core structure is advantageous for coupling and leakage, because the magnetic flux density is relatively large (material, related to the thickness of the sheet), and the second is because of the primary relative secondary The distributed capacitance is the thicker the layer in parallel or the larger the distributed capacitance. The unique physical structure of the c-type core is more conducive to medium to high transmission! However, the C-type iron core also has the disadvantage of poor overload capability. The reason why the sheet is too thin and the lamination factor is too good, but it cannot withstand the shock and overload caused by the back electromotive force of the speaker, not to mention the stronger the counter-electromotive force of the speaker with higher power, so we Independently designed and developed C cattle products, whether it is single-ended or push-pull output transformers are controlled below 30W, audio is a science, we constantly strive to explore every moment! We insist on good sound and low price products is the direction of future development. . . . . . .
Specifications:
Material: British amorphous 4C core
Impedance: 10Kpp (0-4-8) (default without super linear pumping, can be customized with 16 ohm impedance output)
Impedance: P1----P2 (358 ohms) P1-----B+----P2 (178 ohm upper and lower arm error less than 1 ohm) 0-8 ohms (0.5 ohm)
Inductance: P1--------P2 (about 33H)
Bandwidth: 20HZ----------40khz (-1db)
Weight: 1kg
Three-dimensional: 88*68*76
I would appreciate what you think would be worth trying
Thanks
(I have no link with any of these )
I am going to build an EL84 or 6P14P-EV PP amp.
Can you give some feed back on the following transformers with pros and cons and if it were you what would you order?
No.1
The first ones are
￡34.13 | 12W 8K/10k small push-pull output transformer, 6P1，EL84，6v6 tube amplifier output transformer, Primary overcurrent ≥80ma
12W 8K/10k small push pull output transformer, 6P1，EL84，6v6 tube amplifier output transformer, Primary overcurrent ≥80ma|Transformers| - AliExpress
Description
High quality 12W 8K/10k small push-pull output transformer
Steel sheet size: 66*30m (tongue width 22*30)
Manufacturer: Kawasaki, Japan
Primary resistance: PP 10K (resistance can be adjusted as required or super linear taps can be added)
Level impedance: 0-4-8Ω
Primary DC resistance: P-P248Ω, the error of the two arms is less than 0.5%
Grade DC resistance: 0-4: 0.35Ω, 0-8: 0.45Ω
Primary inductance: 28H
Primary overcurrent: not less than 80ma
Frequency response: 8-50KH z-1db, 20-35KHZ -0.3db
Withstand voltage: 2000Vdc
Weight: 1.85KG (net weight, without potting)
No.2
Going up in price are these ones
￡42.96 | 12W 8K: 4Ω 8Ω ultra-linear push-pull output transformer, 40H, suitable for 6P6P, 6V6, EL84, 6P14, 6BQ5 push-pull amplifier
12W 8K: 4Ω 8Ω ultra linear push pull output transformer, 40H, suitable for 6P6P, 6V6, EL84, 6P14, 6BQ5 push pull amplifier|Transformers| - AliExpress
Description
Luge PW-1 broadband response ultra-linear push-pull 8K/4Ω 8Ω output transformer, imitating the output transformer of Shanghai Meiduo brand electron tube R10-2 amplifier.
Mido R10-2 high-fidelity amplifier domestic classic HIFI amplifier, launched by Shanghai Radio No. 3 Factory in 1971, was also the most representative high-fidelity tube amplifier at the time. The characteristic of Mido R10-2 high-fidelity amplifier is that it does not hesitate to build Hi-Fi on the output transformer. The output transformer and the power transformer are the same size, which is very rare in the past tube audio. Not only is the material heavy, but the workmanship is very good, the sound is extraordinary.
Mido R10-2 high-fidelity output transformer adopts four-clamp one-winding method, adopts a core with a large cross-sectional area, increases the number of turns of the primary coil, and has a unique winding structure. The effect is outstanding, and the sound quality is now not used to lose thousands Imported transformers of the same specifications.
Z11 core winding measurement system, 76 pieces stacked 40mm thick, wide frequency response, large dynamic, delicate sound! The effect is immediate!
12W8K push-pull amplifier output cattle, suitable for 6P6P, 6V6, EL84, 6P14, 6BQ5 and other tube push-pull amplifier
Iron core is inserted into the core, nylon wire wrapped skeleton, high-quality oxygen-free copper enameled wire winding, using 4 clips 3, positive and negative winding, layered section winding, to minimize leakage inductance and distributed capacitance.
When the parameters are measured at 1KHZ, the inductance of P1 P2 is about 40H, the leakage inductance is about 60mH, and the distributed capacitance is 2300PF.
The primary copper resistance of P1, P2 is about 475Ω, the secondary 4 ohm copper resistance is about 0.5Ω, and the 8Ω copper resistance is about 0.6Ω.
The total volume is 80×69×70mm, and the weight is 2.8Kg/pair.
No.3
The next one is an amorphous C core design
View attachment 1
￡75.20 | 12W Amorphous C-type Core Push-pull Output Transformer Pr10K Se 0-4-8 Ohms for Tube Amplifier 6P1 6P14 EL84
12W Amorphous C type Core Push pull Output Transformer Pr10K Se 0 4 8 Ohms for Tube Amplifier 6P1 6P14 EL84|Transformers| - AliExpress
Amorphous C-type iron core 12W10K push-pull output transformer cattle 6P1.6P14, EL84 push-pull machine for application, layer winding process, CNC drying! Vacuum dipping paint!
Friends of the fever industry have a lot of controversy about the various output transformers that are processed by EI iron core and amorphous iron core. The C core has a good magnetic circuit distribution structure. Similar to the cores of 3,068a and 171 of the Western iron core, this type of core structure is advantageous for coupling and leakage, because the magnetic flux density is relatively large (material, related to the thickness of the sheet), and the second is because of the primary relative secondary The distributed capacitance is the thicker the layer in parallel or the larger the distributed capacitance. The unique physical structure of the c-type core is more conducive to medium to high transmission! However, the C-type iron core also has the disadvantage of poor overload capability. The reason why the sheet is too thin and the lamination factor is too good, but it cannot withstand the shock and overload caused by the back electromotive force of the speaker, not to mention the stronger the counter-electromotive force of the speaker with higher power, so we Independently designed and developed C cattle products, whether it is single-ended or push-pull output transformers are controlled below 30W, audio is a science, we constantly strive to explore every moment! We insist on good sound and low price products is the direction of future development. . . . . . .
Specifications:
Material: British amorphous 4C core
Impedance: 10Kpp (0-4-8) (default without super linear pumping, can be customized with 16 ohm impedance output)
Impedance: P1----P2 (358 ohms) P1-----B+----P2 (178 ohm upper and lower arm error less than 1 ohm) 0-8 ohms (0.5 ohm)
Inductance: P1--------P2 (about 33H)
Bandwidth: 20HZ----------40khz (-1db)
Weight: 1kg
Three-dimensional: 88*68*76
I would appreciate what you think would be worth trying
Thanks
(I have no link with any of these )
Attachments
Last edited:
Looks like you've got links to both single ended and push-pull. Which is it, or are you going to build both?
jeff
jeff
It's hard to judge with Asian trannies. Could be good, bad or mediocre.
Try closer to home maybe.
25W 7600 Ohms Ultra Linear Push Pull Output transformer – Primary Windings
Might cost the same or less by the time you figure in shipping from the orient.
S
Try closer to home maybe.
25W 7600 Ohms Ultra Linear Push Pull Output transformer – Primary Windings
Might cost the same or less by the time you figure in shipping from the orient.
S
How about Novotem Talema Transformers? I can purchase them from RS components.
I am not sure about ordering anything from Europe at the moment post Brexit. There has been a lot of bad press recently about import duty and people being caught out. I had thought that with a free trade deal we were ok but it seems I have misunderstood, and that we have still left the customs union. I think we now pay local vat in Europe plus import charges and vat in UK it’s really pushed prices up.
It’s all a bit of a mess at the moment.
I am not sure about ordering anything from Europe at the moment post Brexit. There has been a lot of bad press recently about import duty and people being caught out. I had thought that with a free trade deal we were ok but it seems I have misunderstood, and that we have still left the customs union. I think we now pay local vat in Europe plus import charges and vat in UK it’s really pushed prices up.
It’s all a bit of a mess at the moment.
Thanks for that!! I was unaware of these guys but I may get a pair of the SE 5K OPTs. I like 5K for the tubes I use like 300b. With extra duty on EU products buying in the UK becomes a priority now.
Do Talema do OPTs? I thought they just did the usual range of toroids.
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Eldar,
The only audio transformers I see available from RS are here:
Audio Transformers | RS Components The second and third ones on the page. Both have primary impedances a little low for EL84s, especially V78A01F. The D29A09F might be a bit better.
Here's the thing, low frequency response and power handling, at least with standard EI transformers, is almost directly related to weight. The D29A09F from RS weighs 0.94 kg. The one I mentioned earlier from Primary Windings weighs 2 kg. More weight = more expensive = deeper, lower distortion bass. The choice may be budgetary, which I can certainly understand.
AFIK, Talema doesn't make output transformers.
Good luck,
Steve
The only audio transformers I see available from RS are here:
Audio Transformers | RS Components The second and third ones on the page. Both have primary impedances a little low for EL84s, especially V78A01F. The D29A09F might be a bit better.
Here's the thing, low frequency response and power handling, at least with standard EI transformers, is almost directly related to weight. The D29A09F from RS weighs 0.94 kg. The one I mentioned earlier from Primary Windings weighs 2 kg. More weight = more expensive = deeper, lower distortion bass. The choice may be budgetary, which I can certainly understand.
AFIK, Talema doesn't make output transformers.
Good luck,
Steve
@eldarvanyar
Many years ago, I ordered from Sowter. I was not subjected to UK VAT. That remains the norm for "mail order". The buyer's jurisdiction of residence gets to tax.
Check with Toroidy. I suspect you "only" pay UK duties and VAT, which are more than painful enough.
Many years ago, I ordered from Sowter. I was not subjected to UK VAT. That remains the norm for "mail order". The buyer's jurisdiction of residence gets to tax.
Check with Toroidy. I suspect you "only" pay UK duties and VAT, which are more than painful enough.
I'm about to order similar OT's from Holland:
20Watt 8kOhm Push-Pull uitgangstrafo
No experience with them (nor hifi OT's at all 😱 ), but Menno van der Veen has worked with them.
20Watt 8kOhm Push-Pull uitgangstrafo
No experience with them (nor hifi OT's at all 😱 ), but Menno van der Veen has worked with them.
Don't know about Canada, it's all a mess and unclear at the moment with Brexit, but it is early days; also add in Covid and the world is rather complicated at the moment.
I can check out Primary Windings as I have used them before for an EAR 834P Phono clone - they designed a PSU and Choke for the project that works really well. John at Primary Windings is very good to deal with and I like to support British Companies at the moment in such difficult times.
My thinking with the Ali Express ones was it might be 'worth a punt' as they are good prices. I have ordered Lundahl and Audio Note OPTS which are much more expensive, for my two other projects and I thought it may be a way to compare.
I can check out Primary Windings as I have used them before for an EAR 834P Phono clone - they designed a PSU and Choke for the project that works really well. John at Primary Windings is very good to deal with and I like to support British Companies at the moment in such difficult times.
My thinking with the Ali Express ones was it might be 'worth a punt' as they are good prices. I have ordered Lundahl and Audio Note OPTS which are much more expensive, for my two other projects and I thought it may be a way to compare.
Amorphous cores are interesting. I have a NP amorphous core 3.5K SE from Vietnam. It's detailed but took a while to break in. I love O-Netics OPTs and have two pairs but Bud isn't working anymore.
Regarding duty on imports into the UK, I recently bought some recording tape online from a firm in Germany at a total cost of £146.40
UPS have requested me to pay a further £51.31 made up of £33.09 "Government Charges" £17.10 "Brokerage" (Their own fees no doubt) and £1.12 "VAT"
How any of that is worked out I do not know - doesn't seem to be any sensible percentage but since I have bought stuff from the same supplier pre Brexit with no added charges I need to think again....
UPS have requested me to pay a further £51.31 made up of £33.09 "Government Charges" £17.10 "Brokerage" (Their own fees no doubt) and £1.12 "VAT"
How any of that is worked out I do not know - doesn't seem to be any sensible percentage but since I have bought stuff from the same supplier pre Brexit with no added charges I need to think again....
Hi
These in use here as RH84 . Built several RH type SE amps These Amorphous trannies very good Quality as good or better as similar Lundahl model ,basic version
20to20, I agree. Hammond is a good one to try shipping to the UK, or finding a distributor there.
eldarvanyar, Hammond is in Canada.
Hopefully some company knows how to get the transformers from Canada to UK.
Perhaps there is a Hammond distributor in the UK.
EL84 Push Pull, right?
Hammonds made for PP EL84:
10 Watts, 8k plate to plate, with Ultra Linear taps, to 4, 8, and 16 Ohms. You can try Pentode mode, Ultra Linear mode, and Triode mode, all on the same transformer.
10 Watts, 10k plate to plate, with Ultra Linear taps, to 4, 8, and 16 Ohms. You can try Pentode mode, Ultra Linear mode, and Triode mode, all on the same transformer.
I recommend purchasing at least 1 to try, build it on a board, and see what you think.
I have one of those 10k plate to plate Hammonds.
I build low power push pull amplifiers in Ultra Linear mode.
I do not run the tubes at more than about 10 Watts per plate dissipation.
I have used that transformer with KT66, KT77, and 6L6GC.
Using a similar 10Watt, 10k plate to plate Ultra Linear transformer from Edcor, I built a similar amplifier with 7591 tubes.
It is in the Tubes / Valves Threads. it is called:
" A Simple Low Power 7591 Push Pull Amplifier "
Click and paste the title above into this forum's Search Forums Box, and you will find that Thread.
It may not be your 'cup of tea', but it is food for thought.
Someday, If I ever get the time, energy and desire, I will do some measurements of that 7591 amp, and post the results on that thread.
eldarvanyar, Hammond is in Canada.
Hopefully some company knows how to get the transformers from Canada to UK.
Perhaps there is a Hammond distributor in the UK.
EL84 Push Pull, right?
Hammonds made for PP EL84:
10 Watts, 8k plate to plate, with Ultra Linear taps, to 4, 8, and 16 Ohms. You can try Pentode mode, Ultra Linear mode, and Triode mode, all on the same transformer.
10 Watts, 10k plate to plate, with Ultra Linear taps, to 4, 8, and 16 Ohms. You can try Pentode mode, Ultra Linear mode, and Triode mode, all on the same transformer.
I recommend purchasing at least 1 to try, build it on a board, and see what you think.
I have one of those 10k plate to plate Hammonds.
I build low power push pull amplifiers in Ultra Linear mode.
I do not run the tubes at more than about 10 Watts per plate dissipation.
I have used that transformer with KT66, KT77, and 6L6GC.
Using a similar 10Watt, 10k plate to plate Ultra Linear transformer from Edcor, I built a similar amplifier with 7591 tubes.
It is in the Tubes / Valves Threads. it is called:
" A Simple Low Power 7591 Push Pull Amplifier "
Click and paste the title above into this forum's Search Forums Box, and you will find that Thread.
It may not be your 'cup of tea', but it is food for thought.
Someday, If I ever get the time, energy and desire, I will do some measurements of that 7591 amp, and post the results on that thread.
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This is what I have been reading in the press recently that people are being online from sellers in Europe and are now paying a high percentage on import fees and 'brokerage fees' from the post office or courier. It is making it very difficult to order from the EU at this point.